Electric furnace



Jm, zz, 1925. "31,524,539

o. A. coLaY ELECTRIC FURNAGY Filed Nov J5, 1921 2 ShutShent 1 Jui, 27, 925. Y 1,524,539- O. A. COLBY ELECTRIC FURNACE Filed Nov. 16, 1921 2 Sheats-Sheet 2 ffy@ ,5 22 om NN/T l* /9 BY @14M @LA7/@M ATTORNEY NlTED STATES PATENT OFFICE.

ORA A. COLBY, OF IRWIN, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC la EEANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRIC Application filed November 16, 1921.

To @ZZ 70710111 f 11mg/ Concern.'

Ile it known that I, ORA A. CoLnr, a citiof the United States, and a resident of Irwin, in the county of Testmoreland and State of Pennsylvania, have invented a new and useful Improvement in Electric Furnaces, of which the following' is a specification.

My invention relates to electric furnaces and particularly to electric-resistance furnaces. and it has for its object to provide a relatively simple heating element for an electric-resistance furnace.

In practising my invention, more particularly in connection with relatively small furnaces, I provide a plurality of relativelyv thin refractory plates each having a plurality of spaced and alined integral projections on one surface thereof and a relatively heavy and unyielding performed resistor member having a plurality of integral spaced looped portions, which loosely engage the projections on the refractory member,

In practising my invention, particularly with reference to relatively large furn'aces, I provide a plurality of spaced alined hook members supported by the walls and the roof of the furnace and mount the hereinbefore described looped resistor member thereon, the looped portions operatively engaging the hook members.

In the drawings,

Figure 1 is a view.y in vertical lateral cross section, of an electric-resistance furnace comprising the device embodying my invention.

Fig. Q is a fragmentary view, in front elevation, of a heating element embodying my invention.

Fig. 8 is a view of a modified form of heating element,

Fig. -l is a fragmentary view, in lateral cross section, of a heating element illustrated in Fig. 2, taken on the line IV-IV;

Fig. 5 is a view, in vertical cross section, of a relatively largeI furnace comprising the device embodying my invention, taken on the line V-V of Fig. 6;

Fig. 6 is a view, in horizontal section, taken on the line VI-VI of Fig. 5;

Fig. 'l' is 'a view, in front elevation, of a hook member and an associated loop portion of a resistor member, and

FURNACE.

Serial No. 515,527.

Fig. 8 is a view, in side elevation, of the parts illustrated in Fig. 7.

An electric-resistance furnace 1() comprises an outer metallic framework 11, 'a plurality of supporting members 12, an outer lining 13 composed of a plurality of bricks or blocks of a suitable refractory heat-insulating material and an inner lining 14; composed of a plurality of bricks or blocks of a suitable high-temperature-resisting refractory material, the bricks or blocks in the two linings being so spaced as to form a furnace chamber 15 of any suitable or desired contour and dimensions.

A plurality of relatively thin refractory plates 16, of substantially rectangular contour, each provided with a plurality of integral spaced projections 17 constitute the muiiie or walls of the furnace chamber, the surface of the plates upon which the projections are located being so placed as to face the walls of the chamber. The projections 1T are alined both longitudinally and laterally of the plate 16 and are located in depressions 1S in the surface of the plate. An electric furn'ace comprising a substantially similar refractory plate having a plurality of rows of small integral projections operatively alined both longitudinally and laterally of the plate, is disclosed and claimed in a co-pending application of T. A. Reid and myself, Serial No. 449,685, filed March 5, 1921, and assioned to the lVestinghouse Electric & Manufacturing Company.

The resistor member 19 comprises a relatively heavy and unyielding rod or bar of a suitable resistor material which is so preformed as to comprise a plurality of integral spaced loops and a plurality of integral endconnected and substantially parallel extending convolutions. I may so preform the resistor member 19, both with regard to the looped portions and with regard to the convolutions, as to permit of so mounting the resistor member on the plate as to cause the convolutions to extend longitudinally thereof, substantially as illustrated in Fig. 2, or I may so preform the resistor member as to permit mounting it laterally thereof, as indicated in the broken lines of Fig. 2 or, if desired, or required by the furnace construction, I may so preform it as to mount the same on the plate with the convolutions extending diagonally thereof, substantially as illustrated in Fig. lt is, of course, apparent th'at the resistor member must be preformed to permit of its being mounted in any of the hereinbefore described positions on tlic refractory plate 16 and that it is impossible to change the resistor member from one to another of the illustrated positions after being so preformed. The loop portions are made relatively large so that they will engage the projections 1T loosely to permit of expansion and contraction of the substantially straight portions during the operation of the furnace and of allowing for ordinary variations in the distance between projec tions 17, as may occur in the manufacture of the refractory plates.

Referring particularly to Figs. 5 to 8, inclusive, a furnace 10 comprises an outer metallic framework 11, supporting members 12, an outer lining 13 and an inner lining 14, substantially as here-inbefore described in connection with Fig. 1.

The inner lining 14 is spaced apart at suitable intervals to provide openings 20 of substantially T-shape, to permit of locating therein a plurality of refractory members 21 also of substantially T-shape, the narrow portion of the member projecting through the inner lining into the furnace chamber 15. A metal hook member 22 is'mounted in each o-f the refractory supporting members 21, the hook portions of the member 22 eX- tending substantially vertically upward when mounted in the side walls of the furnace.

A resistor member 19, of substantially the same construction as hereinbefore described in connection with the refractory plates illustrated in Figs. 1 to t, is so mounted on the hook members 22 as to cause the loop portions thereof to engage the same and be supported thereby. The internal diameter of the looped portions is made relatively large, as compared with the dimensions of the hook portion of the members 22, to permit of the loop being easily and quickly slipped over the hook portion when mounting the resistor in the furnace chamber or of easily and quickly removing the same therefrom whenever this becomes necessary. The relatively large loop portions also permit of the expansion and contraction of those portions of the resistor between the loop portions without causing any undue stress upon the hook portions during the operation of the furnace. It is to be noted that the resistor member 19, as employed in the type of furnace illustrated in Figs. 5 to 8, comprises a plurality of substantially parallel extending end-connected convolutions, each convolution comprising a.` plurality of spaced loop portions, and that the resistor members may be suitably connected to each other and to suitable supply-circuit conductors (not shown) in a manner well known in the art.

The device embodying my invention thus provides a relatively simple preformed resistor member of relatively heavy and unyielding material comprising a plurality of integral end-connected convolutions each having a plurality of spaced looped portions loosely engaging supporting means substantially self-supporting between the looped portions, and which may be quickly inserted in, and removed from, the furnace with which it is associated.

Various modifications may be made in the device embodying my invention without departing from the spirit and scope thereof and l desire that only such limitations shall be placed thereon as are imposed by the prior art or are specifically set forth in the appended claims.

l claim as my invention:

1. In an electric furnace, the combination with a refractory wall, and a plurality of spaced sets of alined spaced metal hook members supported by said wall, of a relatively heavy resistor member preformed to comprise a plurality of substantially parallel-extending convolutions, each convolution having a plurality of integral loops for operatively engaging a set of alined hook members.

2. ln an electric furnace. the combination with a refractory wall, a plurality of refractory members. of substantially T-shape.. mounted in said wall, and a plurality of metal hook members mounted in the respective refractory members and projecting away from said wall, of a relatively heavy resistor member preformed to comprise a plurality of substantially straight and parallel-extending convolutions, each convolution having a plurality of spaced loops for operatively engaging a plurality of hook members to permit of supporting said resistor adjacent to said wall and for permitting` of free longitudinal movement thereof during operation of the furnace.

ln testimony whereof. I have hereunto subscribed my name this 2nd day of November, 1921.

ORA A. COLBY. 

